Eco-roof helps solve high-rise height problem

Jerry Eekhoff represents the developers of The Beacon, a proposed mixed-use building on Southwest Sixth Avenue, near Portland State University. The city’s Design Commission is scheduled to vote on the project on Thursday. (Photo by Dan Carter/DJC)

The developers of a Portland high-rise last year sought to build higher than allowed by transferring development rights from a downtown historic building. A city panel suggested another approach, sending the builders back to the drawing board.

Now they’re proposing to build an eco-roof in order to gain extra building height.

The mixed-use project, known as The Beacon, is on Southwest Sixth Avenue near Portland State University. The rooftops of the building’s 13-story and nine-story towers, along with a small portion of a second-floor roof, will be covered by a combined 6,668 square feet of eco-roof, more than 60 percent of the total footprint, according to a city Bureau of Development Services report.

A vote by the city’s Design Commission on the project, formerly known as College Station, is scheduled for Thursday.

Meanwhile, at least two other planned high-rises in downtown could gain height by including eco-roofs, said Christine Caruso, the Portland city planner overseeing The Beacon. She declined to identify the projects because, she said, plans have not been finalized.

Brent Grubb, an architect with Skylab Architecture, said the company’s planned Weave Building, at the corner of West Burnside Street and Southwest 13th Avenue, will have an eco-roof. He said this will earn the building an extra two floors of space, allowing it to be a maximum of 12 stories.

As for The Beacon, “they ended up doing the eco-roof as one of the only ways to get what they needed,” Caruso said.

The bonus, which provides up to 3 square feet of extra floor area for every square foot of eco-roof­, is not new. According to Troy Doss, a senior planner with the city’s Bureau of Planning and Sustainability, the option has been available for roughly eight years. He could not immediately confirm how many buildings have received the bonus.

But in the past five years, he said, eco-roofs have become increasingly popular, especially in the Pearl District and in the South Waterfront District, where, he said, “just about all” new projects have it.

The Beacon, a proposed mixed-used building near Portland State University, was supposed to be a maximum 125 feet tall, but by adding eco-roofing, its developers can add up to an extra 45 feet of height. (Photo courtesy Jerry Eekhoff)

And, he said, many new eco-roofs are built not to earn height extensions, but to help projects achieve Leadership in Energy and Environmental Design certification.

When the bonus was introduced, Doss noted, green roofs were not the industry standard, and builders were afraid of leaks or roofs burdened by excessive weight.

“It’s less bonus-driven at this point than general practice by a lot of people,” Doss said.

Nevertheless, The Beacon, without any bonuses, is allowed to be 125 feet tall. According to the development services report, its planned eco-roof and art exhibit have earned the project an extra 45 feet of height.

The developers, though, are asking for only an additional 18.5 feet. Their representative, Jerry Eekhoff, principal of Portland-based W.E. Develop, did not say why they aren’t using the full bonus.

The developers originally sought to build a student housing complex at the site and, to earn more height, transfer development rights from the historic Henry Building.

But this transfer would have required City Council approval, which, according to Caruso, would have required the project include some kind of public benefit, like a park.

The development apparently lacked that.

“Just building a new building is not necessarily a public benefit,” Caruso said. “It’s bigger than that.”

According to the city, eco-roofs – often comprised of grass, plants and other vegetation – reduce storm water run-off and provide habitat for birds, among other benefits.

“It was better for the project,” Eekhoff said of the eco-roof. “It’s a green building.”

The Beacon’s ground-breaking is at least eight months away, he said.

Meanwhile, the city offers other incentive programs to add eco-roofs, such as grants of $5 for every square foot of green roof built.

The grant program, which started in July 2008, has had three funding cycles, the most recent of which ended this month.

According to Alice Meyers, environmental specialist with Portland’s Bureau of Environmental Services, the city has approved $700,000 in funding, all of which is contingent upon the roofs being built.

“And we inspect,” said Amy Chomowicz, the city’s eco-roof program administrator. “We even confirm the final square footage.”